What is the major role of 2, 3 bisphosphoglycerate in RBCs?

2,3 BPG is responsible for significantly lowering the oxygen affinity of hemoglobin and and allowing the hemoglobin to more efficiently release oxygen at the typical Po2 of tissues. Only one molecule of 2,3 BPG interact with each hemoglobin tetramer. Rise in 2,3 BPG in RBCs promotes the shift of hemoglobin to the T form and subsequently release oxygen. In rbcs 2, 3 BPG rise as they adapt to conditions of tissue hypoxia ( from anemia, high altitude, pulmonary dysfunction).